Recordable multilayer optical disk, recording method, reproducing method, and recording apparatus

Abstract

For example, a recordable single-sided two-layer optical disk which is recorded into and reproduced from with light whose wavelength is 405 nm is so configured that, if the front layer is an L0 layer and the inner layer is an L1 layer when viewed from the light entrance surface (or the light-receiving surface), the absorbance of the L1 layer in the wavelength range of 600 to 800 nm is higher than that of the L0 layer. In a part of the L1 layer whose absorbance to light in the range of 600 to 800 nm is high, an area (BCA) in which specific information on the optical disk is to be recorded is provided.

1 . In an optical disk where a plurality of recording layers are stacked one on top of another, each recording layer being recorded into and reproduced from with light whose wavelength is in the range from blue-violet to blue, a recordable multilayer optical disk being so configured that, if a front layer is an L0 layer and an inner layer is an L1 layer when viewed from the light entrance surface, the absorbance of the L1 layer in the wavelength range of 600 to 800 nm is higher than that of the L0 layer. 
   
   
       2 . The optical disk according to  claim 1 , wherein the L1 layer has a burst cutting area in which specific information is recorded with light whose wavelength is in the range of 600 to 800 nm in an area closer to the inner edge of the disk than a data area in which information is recorded with light whose wavelength is 450 nm or less,
 a first organic material having a high absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the burst cutting area, and   a second organic material having a relatively low absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the L0 layer overlapping with the burst cutting area.   
   
   
       3 . The optical disk according to  claim 2 , wherein the first organic material is used for the burst cutting area of the L1 layer or both the burst cutting area and the data area of the L1 layer. 
   
   
       4 . The optical disk according to  claim 2 , wherein an organic material whose absorbance in the wavelength range of 600 to 800 nm is equal to or more than half the absorbance at a wavelength of about 405 nm is used as the first organic material used for the L1 layer. 
   
   
       5 . The optical disk according to  claim 3 , wherein an organic material whose absorbance in the wavelength range of 600 to 800 nm is equal to or more than half the absorbance at a wavelength of about 405 nm is used as the first organic material used for the L1 layer. 
   
   
       6 . The optical disk according to  claim 4 , wherein the first organic material used for the burst cutting area of the L1 layer is composed of an organic metal complex including central metal M, a first organic pigment having sensitivity to light whose wavelength is about 405 nm, and a second organic pigment having sensitivity to light whose wavelength is in the range of 600 to 800 nm,
 the central metal M includes cobalt or nickel,   the first organic pigment includes cyanine pigment, styryl pigment, or monomethine cyanine pigment, and   the second organic pigment includes azo pigment, cyanine pigment, or phthalocyanine pigment.   
   
   
       7 . The optical disk according to  claim 5 , wherein the first organic material used for the burst cutting area of the L1 layer is composed of an organic metal complex including central metal M, a first organic pigment having sensitivity to light whose wavelength is about 405 nm, and a second organic pigment having sensitivity to light whose wavelength is in the range of 600 to 800 nm,
 the central metal M includes cobalt or nickel,   the first organic pigment includes cyanine pigment, styryl pigment, or monomethine cyanine pigment, and   the second organic pigment includes azo pigment, cyanine pigment, or phthalocyanine pigment.   
   
   
       8 . The optical disk according to  claim 2 , wherein an organic material whose absorbance in the wavelength range of 600 to 800 nm is equal to or less than half the absorbance at a wavelength of about 405 nm is used as the second organic material used for the L0 layer. 
   
   
       9 . The optical disk according to  claim 3 , wherein an organic material whose absorbance in the wavelength range of 600 to 800 nm is equal to or less than half the absorbance at a wavelength of about 405 nm is used as the second organic material used for the L0 layer. 
   
   
       10 . The optical disk according to  claim 8 , wherein the second organic material used for the L0 layer is composed of an organic metal complex including central metal M and an organic pigment having sensitivity to light whose wavelength is about 405 nm,
 the central metal M includes cobalt or nickel, and   the organic pigment includes cyanine pigment, styryl pigment, or monomethine cyanine pigment.   
   
   
       11 . The optical disk according to  claim 9 , wherein the second organic material used for the L0 layer is composed of an organic metal complex including central metal M and an organic pigment having sensitivity to light whose wavelength is about 405 nm,
 the central metal M includes cobalt or nickel, and   the organic pigment includes cyanine pigment, styryl pigment, or monomethine cyanine pigment.   
   
   
       12 . In a recordable multilayer optical disk, where a plurality of recording layers are stacked one on top of another, each recording layer being recorded into and reproduced from with light whose wavelength is in the range from blue-violet to blue, being so configured that, if a front layer is an L0 layer and an inner layer is an L1 layer when viewed from the light entrance surface, the absorbance of the L1 layer in the wavelength range of 600 to 800 nm is higher than that of the L0 layer, wherein the L1 layer has a burst cutting area in which specific information is recorded with light whose wavelength is in the range of 600 to 800 nm in an area closer to the inner edge of the disk than a data area in which information is recorded with light whose wavelength is 450 nm or less, a first organic material having a high absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the burst cutting area, and a second organic material having a relatively low absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the L0 layer overlapping with the burst cutting area,
 an information recording method comprising irradiating laser light whose wavelength is in the range of 600 to 800 nm onto the burst cutting area of the L1 layer through the L0 layer in the optical disk and thereby recording specific information on the optical disk into the burst cutting area.   
   
   
       13 . In a recordable multilayer optical disk, where a plurality of recording layers are stacked one on top of another, each recording layer being recorded into and reproduced from with light whose wavelength is in the range from blue-violet to blue, being so configured that, if a front layer is an L0 layer and an inner layer is an L1 layer when viewed from the light entrance surface, the absorbance of the L1 layer in the wavelength range of 600 to 800 nm is higher than that of the L0 layer, wherein the L1 layer has a burst cutting area in which specific information is recorded with light whose wavelength is in the range of 600 to 800 nm in an area closer to the inner edge of the disk than a data area in which information is recorded with light whose wavelength is 450 nm or less, a first organic material having a high absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the burst cutting area, and a second organic material having a relatively low absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the L0 layer overlapping with the burst cutting area,
 an information reproducing method comprising irradiating laser light onto the burst cutting area of the L1 layer through the L0 layer in the optical disk and thereby reproducing specific information on the optical disk from the burst cutting area.   
   
   
       14 . In a recording apparatus which records information onto a recordable multilayer optical disk, where a plurality of recording layers are stacked one on top of another, each recording layer being recorded into and reproduced from with light whose wavelength is in the range from blue-violet to blue, being so configured that, if a front layer is an L0 layer and an inner layer is an L1 layer when viewed from the light entrance surface, the absorbance of the L1 layer in the wavelength range of 600 to 800 nm is higher than that of the L0 layer, wherein the L1 layer has a burst cutting area in which specific information is recorded with light whose wavelength is in the range of 600 to 800 nm in an area closer to the inner edge of the disk than a data area in which information is recorded with light whose wavelength is 450 nm or less, a first organic material having a high absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the burst cutting area, and a second organic material having a relatively low absorbance to light whose wavelength is in the range of 600 to 800 nm is used for the L0 layer overlapping with the burst cutting area,
 the recording apparatus comprising:   means for generating specific information to be recorded into the burst cutting area, and   means for recording the specific information into the burst cutting area of L1 layer through the L0 layer using laser light whose wavelength is in the range of 600 to 800 nm.